My mother in law (from China) n my husband had a huge fight and she left the house today morning and still have not return. She also switch off her phone. She is 70 and only speaks Mandarin. Husband heck care. I dont know what to do. Should I go to the police?

Check with relatives or friends. If no, find around your neighbourhood. She might not gone far. Also checked her belongings & passport. U never know if she goes back to China in a fit of anger. Actually best way now is to make use of social media platform! Post her photo with description, can help to locate her. If u report police now they will just take ur statement but unable to take further actions now. Have to wait 24 hrs. Dun panicked. She will be fine!